Production of metaldehyde



Patented Dec. 28, 1925.

UNITED STATES PATENT lorries.-

THEODOR LIOHTENEAHN, 013' 7151', AND EMIL L'U'SCHER AND HEINRICH STEIGER, OI BASEL, SWITZERLAND, ASSIGNOBS TO THE FIRM ELEKTBIZITKTSWERK LONZA, OF

GAMIEL, SWITZERLAND.

PRODUCTION or METALDEHYDE.

No Drawing. Application filed June 10, 1925, Serial No. 36,278, and in Germany i'une 23, 1924.

The metaldchyde produced according to U. S. Letters Patent No. 1,555,223, from metal salts and acids and pressed into cakes or press bodies is generally covered some time after lighting by a fine grey to black coating, which hinders the combustion of the block. Research has now shown that the cause of this difliculty is to be found in the residue of the catalyst still remaining in the finished product, although the incombustible residue of the catalyst exists in the metaldehyde only in extremely small quan tity, at most a few thousandths per cent, and consequently cannot by itself alone produce so much troublesome ash. It has also been found that several inorganic residues although contained in much larger quantities in the metaldehyde do not affect the combustion to a noticeable degree.

action, which during the combustion, especially with insufficient air supply, causes the formation; of carbonaceousslag on the metaldehyde bloclgwhich after the combustion have a dry or greasy appearance. These difliculties cannot be removed by a ,further purification of the metaldehyde, be-

cause that would involve almost insuperable difliculties.

slight extent if in the production of metaldehyde from acctaldehyde, substances are used as catalysts which during the combustion process evaporate, burn themselves or are separated into their constituent parts, which do not act prejudicially on the unburnt metaldehydeand which at the same time, especially with the use, of an excess ,of acid according to the aforesaid patent It follows therefore that this catalyst residue produces by-products by contact re- 'We have now discovered that thae culties do not occur or only occur to a very application, quickly furnish a very good yield of metaldehyde. especially if the catalyst and the acetaldehyde are 'both used in catalysts.

a neutral or acid salt, or can itself be produced in the reacting material, the acetaldehyde being first treated with the baseand then with the necessary quantity of acid.

What we claim is:

dehyde which burns practically free from.

process for the production ofmetal acetate of quinoline. It seems that halo en. derivatives of pyridine are very: suita 1c The catalyst can be added in the form of soot and ash, consisting in treating acetaldehyde with such catalyzer salts that result from the action ,of strong. acids on organic nitrogen bases.

l 2. A process for the production of metal-..

dehyde which burns practicallyfree from soot and ash, consisting in treating acetaldehyde witha"-halogen derivative of pyridine as catalyst.

In witness whereof we have hereunto signed our names this, 29th day of May, 1925.

THEODQR LICHTENHAHN. EMIL LUSOHER.

HEINRICH STEIGER, 

